Surgical operations are carried out in a variety of fields, including surgery, along with the development of medical technology, and surgical site infections have attracted attention as a risk.
Infections in the surgical field are caused in the perioperative period before or after surgery. More particularly, as infections before surgery, peritonitis (intraperitoneal abscess), severe pancreatitis, and severe intestinal ischemia are known. As for infections after surgery, intraperitoneal abscess, catheter infection, pneumonia, and urinary tract infection are known. Surgical site infections exhibit high severity, and a fast, accurate diagnosis is required for early treatment decisions.
In the current diagnosis of surgical site infections, blood culture, white blood cell count, body temperature, diagnostic imaging, the duration of systemic inflammatory response syndrome (SIRS), blood biochemical findings such as a C-reactive protein (CRP) value, and the like, are used as an index. Of these indices, blood culture shows a low positive rate for infections, and requires 3 to 7 days to obtain the test results, and thus, it is difficult to reflect the treatment at present (Non-patent literature 1). Further, fever and increase in white blood cell count and CRP level immediately after surgery are natural results, and thus, these are not specific indices (Non-patent literature 2). Although it is known that a transition risk to multiple organ failure is increased when the number of SIRS-positive items is increased, the duration varies (about 1 to 3 days) due to surgical stress, and thus, the number of SIRS-positive items is not a specific marker for infection. In addition, procalcitonin (PCT) has recently come to be widely used as a bacterial infection marker, but it is known that its blood level is increased even due to injury, which is not accompanied by infection and is highly invasive, and that the PCT produces a false-positive result in an infection diagnosis (Non-patent literature 3).
As described above, no markers effective in the diagnosis of surgical site infections have been reported yet, and doctors are really struggling against the diagnosis of surgical site infections, and the discovery of such markers is highly desired.